html, body {
    height: 100%;
}

#box {
    /*三个属性集合使用,达到撑满剩余高度*/
    display: flex;
    flex-flow: column;
    height: 100%;
}

#box .box-header {
    height: 60px;
    width: 100%;
    background-color: white;
    display: flex; /*使子类div一行显示*/
    font-family: "Helvetica Neue", Helvetica, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "微软雅黑", Arial, sans-serif;
}

#box .box-header table {
    margin: auto;
    font-size: 25px;
    font-weight: bold;

}

#box .box-subject {
    flex: 1;  /*集合父类使用,使其撑满剩余高度*/
    display: flex; /*使子类div一行显示*/
    overflow: hidden; /*溢出隐藏*/
}
#box .box-subject .left {
    width: 8%;
    height: 100%;
    background-color: white;
    font-family: "Helvetica Neue", Helvetica, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "微软雅黑", Arial, sans-serif;
    color: #454647;
}
#box .box-subject .left ul li .title{
    /*background-color: red;*/
    margin-top: 10%;
}
#box .box-subject .left ul li .title span{
    margin-left: 10%;
    font-size: 20px;
}
#box .box-subject .left ul li .title img {
    width: 20px;
    height: 20px;
    float: right;
}
#box .box-subject .left ul li .isShow ul {
    font-size: 16px;
    list-style: none; /*ul标签去掉小黑点*/
}
#box .box-subject .left ul li .isShow ul li {
    margin-top: 10%;
    margin-left: 10%;
}

#box .box-subject .right {
    width: 92%;
    height: 100%;
    background-color: #fefdfd;
}